Nick Piggin wrote:> I have patches to move the tlb flushing to an asynchronous process context...> but all tweaks to that (including flushing at vmap) are just variations on the> existing flushing scheme and don't solve your problem, so I don't think we> really need to change that for the moment (my patches are mainly for latency> improvement and to allow vunmap to be usable from interrupt context).>

Well, that's basically what I want - I want to use vunmap in an interrupts-disabled context. Any other possibility of deferring tlb flushes is pure bonus and not all that important.

But it also occurred to me that Xen doesn't use IPIs for cross-cpu TLB flushes (it goes to hypercall), so it shouldn't be an issue anyway. I haven't had a chance to look at what's really going on there.